Floating daughter card system and method

ABSTRACT

A blade includes both a motherboard and daughter card to allow the combined functionality to be incorporated into a single black for size reduction. Standoffs couple the daughter card to the motherboard. Cantilever portions of the motherboard and daughter card exist between the standoffs and terminals of the motherboard and daughter card. The cantilever portions bend to accommodate any misalignment between the terminals of the motherboard and the daughter card and mating connectors of a bulkhead or printed circuit board backplane.

RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 14/448,796 filed on Jul. 31, 2014, which claims the benefit ofU.S. Provisional Application No. 61/915,986 filed on Dec. 13, 2013,entitled “FLOATING DAUGHTER CARD SYSTEM AND METHOD” of Vanderveen etal., each of which is incorporated herein by reference in its entirety.

BACKGROUND

Field

The present application relates to the field of electronics, and moreparticularly, to structures for electronic devices and related methods.

Description of the Related Art

In a traditional switch, a printed circuit board (PCB) backplane hasconnectors that interface with blades of the switch. The PCB backplaneincludes a dielectric core and electrically conductive traces supportedby the dielectric core. Signals between blades and generally betweencomponents of the switch are propagated along the conductive traces.

However, as more functionality and components are combined to formlarger switches, the number and density of connections to the PCBbackplane to interconnect the various components correspondinglyincreases. Tolerance in the alignment of the connectors can lead tochallenges in assembly and maintenance of the switch.

SUMMARY

In accordance with one embodiment, a blade includes both a motherboardand daughter card to allow the combined functionality to be incorporatedinto a single blade for size reduction. Standoffs couple the daughtercard to the motherboard. Cantilever portions of the motherboard anddaughter card exist between the standoffs and terminals of themotherboard and daughter card. The cantilever portions bend toaccommodate any misalignment between the terminals of the motherboardand the daughter card and mating connectors of a bulkhead or printedcircuit board backplane.

In accordance with another embodiment, springs allow the daughter cardto float relative to the motherboard. The float accommodates anymisalignment between the terminals of the motherboard and the daughtercard and mating connectors of a bulkhead or printed circuit boardbackplane.

In accordance with yet another embodiment, the terminals of the daughtercard and motherboard are fixed in position. Fixed and floatingconnectors are coupled to a bulkhead. The fixed connector is fixed inposition relative to the bulkhead and the floating connector is moveablerelative to the bulkhead. The floating connector is configured toaccommodate tolerance in the positioning of the terminals of themotherboard and the daughter card with respect to the fixed connectorand the floating connector.

These and other features in accordance with various embodiments will bemore readily apparent from the detailed description set forth belowtaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side schematic diagram of an electronic device in accordancewith one embodiment.

FIG. 2 is a cross-sectional view of a blade and a bulkhead assembly inaccordance with one embodiment.

FIG. 3 is a cross-sectional view of a blade and a bulkhead assembly inaccordance with another embodiment.

FIG. 4 is a cross-sectional view of a blade and a bulkhead assembly inaccordance with yet another embodiment.

FIG. 5 is a top plan view of a blade and a bulkhead assembly inaccordance with another embodiment.

FIG. 6 is a cross-sectional view of the blade and the bulkhead assemblyalong the line VI-VI of FIG. 5 in accordance with one embodiment.

In the following description, the same or similar elements are labeledwith the same or similar reference numbers.

DETAILED DESCRIPTION

FIG. 1 is a side schematic diagram of an electronic device 100, e.g., aswitch, in accordance with one embodiment. Electronic device 100includes a chassis 102 that forms that framework that supports thevarious components of electronic device 100.

Generally, electronic device 100 includes a horizontal base 104, e.g.,that extends in a first direction. Electronic device 100 furtherincludes a vertical front face 106, e.g., that extends in a seconddirection perpendicular to the first direction of horizontal base 104.Electronic device 100 further includes a vertical rear face 108 thatalso extends in the second direction perpendicular to the firstdirection of horizontal base 104. For discussion purposes herein, frontface 106 is in a vertical front plane of electronic device 100 and rearface 108 is an approximately parallel vertical rear plane of electronicdevice 100.

Electronic device 100 further includes a horizontal top 110 parallel tobase 104 and perpendicular to faces 106, 108. Faces 106, 108 extendbetween base 104 and top 110. Although the terms vertical, horizontaland similar terms are used herein, the terms are used for simplicity togenerally mean in a first direction and a perpendicular second directionand it is to be understood that the terms are not gravitationallyreferenced.

Located within chassis 102 is a bulkhead 112. In one embodiment,bulkhead 112 is a flat plate, e.g., a machined aluminum plate, extendingin the vertical direction. Bulkhead 112 includes cutouts and otheropenings to accommodate various components of electronic device 100.

One or more cable cassettes 114 are coupled to bulkhead 112. Cablecassettes 114 include internal cabling and connectors that mount to thecutouts in bulkhead 112. This cabling allows high speed signalpropagation thus allowing the size of electronic device 100 to berelatively large, i.e., to accommodate a large amount of components.

Further, bulkhead 112 and cable cassettes 114 form a bulkhead assembly116 that replaces a traditional PCB backplane from the standpoint of thecustomer, e.g., the user of electronic device 100. More particularly,one or more blades 118, e.g., line cards, switch fabrics, and/ormanagement modules, can be readily connected to and disconnected frombulkhead assembly 116.

Blades 118 include bulkhead assembly connector ends 120 and oppositewiring ends 122. Bulkhead assembly connector ends 120 mechanically andelectrically interconnect with bulkhead assembly 116.

Wiring ends 122 include various ports or other data structures as wellas mechanical structures, e.g., ejector handles, to allow securement andremoval of blades 118 from chassis 102. For example, external cabling124 is connected to blades 118 at wiring ends 122.

Located at or adjacent rear face 108 of electronic device 100 is one ormore fans 126, sometimes called fan Field Replaceable Units (FRUs). Fans126 circulate air through electronic device 100 to insure electronicdevice 100 including the components therein are maintained at properoperating temperatures.

FIG. 2 is a cross-sectional view of a blade 118A and a bulkhead assembly116A in accordance with one embodiment. Blade 118A includes a bulkheadassembly connector end 120 that mechanically and electricallyinterconnects with bulkhead assembly 116A.

Bulkhead assembly 116A includes a bulkhead 112A and connectors 430 of acable cassette 114A. Bulkhead 112A, cable cassette 114A, and bulkheadassembly 116A are similar to bulkhead 112, cable cassette 114, andbulkhead assembly 116 as described above in reference to FIG. 1.

Cable cassette 114A includes a front template, connectors 430, cabling432, guidepins 436, and a protective cover. The front template andprotective cover are not illustrated for purposes of simplicity.

Cabling 432 of cable cassette 114A, e.g., twin axial cabling, providesintra-cassette connections between connectors 430 of cable cassette114A. Cabling 432 of cable cassette 114A allows connectors 430 to belocated at a distance from one another while allowing high speed data tobe propagated without the losses typical of traditional printed circuitinterconnection systems. Connectors 430 include signal pins (notillustrated) to which blade 118A is electrically connected.

Although a cable cassette 114A is described herein, in otherembodiments, connectors 430 are directly mounted to bulkhead 112Awithout being a part of an integral cable cassette 114A. In yet furtherembodiments, instead of a bulkhead assembly 116A, a printed circuitboard (PCB) backplane includes fixed connectors, e.g., similar toconnectors 430. The connectors are fixed in position to the PCBbackplane. Thus, although a bulkhead assembly is discussed andillustrated herein, in other embodiments, the discussion is equallyapplicable to the fixed connectors of a PCB backplane.

Generally, embodiments herein account for the positional error in ablade connector plugging into a mating connector such as connectors 430.The connector can be on a PCB, a cable, optical, or any other connector.The actual signal connection method can be any one of a number ofdifferent types.

Referring to the embodiment of FIG. 2 again, connectors 430 are fixed tobulkhead 112A such that the position of connectors 430 is fixed.Accordingly, blade 118A is configured to accommodate both the tolerancein the positions of connectors 430 as well as respective terminals 438of blade 118A.

In accordance with this embodiment, blade 118A, e.g., a line card,includes a motherboard 440 and a daughter card 442. Motherboard 440,sometimes called a first or primary board, includes a motherboardprinted circuit board and various electrical components coupled thereto(not shown) in one embodiment. Similarly, daughter card 442, sometimescalled a second board, includes a daughter card PCB and variouselectrical components coupled thereto (not shown) in accordance with oneembodiment. The printed circuit boards each include a dielectric coreand electrically conductive traces supported by the dielectric core.

Although blade 118A is illustrated and discussed herein as including amotherboard 440 and a daughter card 442, in other embodiments,generally, a blade has two or more (many) printed circuit boards (PCBs).Any of the PCBs can be regarded as the fixed one and not just the lowerPCB. The connector(s) can be on either side of the PCB.

Daughter card 442 is mounted to motherboard 440 by mechanical standoffs448. Illustratively, daughter card 442 and motherboard 440 are mountedto standoffs 448 using screws, mechanical fasteners or other mountingtechniques as discussed further below.

Standoffs 448 are rigid structure thus fixing the distance betweendaughter card 442 and motherboard 440. Daughter card 442 is alsoelectrically coupled to motherboard 440, e.g., by a cable interface 444,a traditional mezzanine, cable, or other suitable connector, to formblade 118A.

In one embodiment, blade 118A includes both a motherboard and daughtercard to allow the combined functionality to be incorporated into asingle blade for size reduction. This is in contrast to providing themotherboard and daughter card as separate components, e.g., blades,mounted to bulkhead assembly 116A.

In accordance with this embodiment, blade 118A includes a blade chassis202. Blade chassis 202 is a rigid support structure for blade 118A.Blade chassis 202 is optional, and in one embodiment, blade 118 does notinclude blade chassis 202.

Blade chassis 202 includes a blade chassis base 204 parallel tomotherboard 440 and daughter card 442. Blade chassis base 204 includesthreaded spacers 206 protruding from blade chassis base 204. Threadedspacers 206 include threaded apertures 208.

Standoffs 448 include threaded screw portions 210 protruding frommotherboard shoulders 212 of standoffs 448, sometimes called firstshoulders 212. Threaded screw portions 210 and more generally standoffs448 are passed through standoffs openings 214 in motherboard 440 andthreaded into threaded apertures 208 of threaded spacers 206. Standoffs448 are threaded into threaded spacers 206 to compress motherboard 440between threaded spacers 206 and motherboard shoulders 212. In thismanner, motherboard 440 is mounted to blade chassis 202.

Standoffs 448 further include threaded apertures 216 extending intostandoffs 448 from daughter card shoulders 218 of standoffs 448,sometimes called second shoulders 218. Threaded screws 220 are passedthrough standoffs openings 222 in daughter card 442 and threaded intothreaded apertures 216 of standoffs 448. Threaded screws 220 arethreaded into standoffs 448 to compress daughter card 442 betweenstandoffs 448, i.e., daughter card shoulders 218, and screw heads 224 ofthreaded screws 220. In this manner, daughter card 442 is mounted tomotherboard 440.

Although one particular assembly of blade chassis 202, motherboard 440,daughter card 442, standoffs 448, and threaded screws 220 is set forth,in other embodiments, motherboard 440 is mounted to daughter card 442 bystandoffs 448 in a different manner.

At bulkhead assembly connector end 120 of blade 118A, motherboard 440includes terminal 438A and daughter card 442 includes terminal 438B.Terminals 438A, 438B are collectively referred to as terminals 438.

Standoffs 448 include one or more cantilever standoffs 448A and one ormore wiring end standoffs 448B. Cantilever standoffs 448A are thosestandoffs 448 nearest terminals 438 whereas wiring end standoffs 448Bare those standoffs 448 near the opposite wiring end 122 of blade 118A.

In accordance with one embodiment, cantilever standoffs 448A are spacedapart by a distance X from the ends of terminals 438 as illustrated.Cantilever portions 450, 452 of motherboard 440 and daughter card 442are defined as those portions of motherboard 440 and daughter card 442,respectively, between cantilever standoffs 448A and the ends ofterminals 438.

Distance X is sufficiently great such that cantilever portions 450, 452of motherboard 440 and daughter card 442 can deflect to match any offsetbetween terminals 438A, 438B and connectors 430 of bulkhead assembly116A without damage to blade 118A including motherboard 440 and daughtercard 442. Stated another way, moving cantilever standoffs 448A away fromterminals 438A, 438B allows for motherboard 440 and/or daughter card 442to deflect in a cantilever effect eliminating the binding condition atterminals 438A, 438B.

To illustrate, the allowable deflection of motherboard 440 and/ordaughter card 442 is 0.010″ deflection, e.g., vertical in the view ofFIG. 2, per 1.00″ of coplanar distance, e.g., horizontal in FIG. 2, inone embodiment. The allowable amount of deflection depends upon theparticular application in other embodiments. For example, the allowabledeflection depends upon the board thickness and the component placementon the boards. As one particular example, high density ball grid array(BGA) based PCBs will be more sensitive to bending than sparselypopulated through hole PCBs. In one example, the amount of micro strainsin the PCBs provides the pass/fail criteria for the allowable amount ofdeflection.

Terminals 438 include guide pin mating apertures 226 into which guidepins 436 of connectors 430 are configured to fit. Guide pins 436 includetapered tips 228, sometimes called pointy tips 228, at the end of a mainbody portion 230 of guide pins 436.

As blade 118A is moved towards connectors 430, tapered tips 228 areinserted into guide pin mating apertures 226. If there is an offsetbetween terminals 438 and connectors 430, cantilever portions 450, 452will bend as guide pins 436 are inserted into guide pin mating apertures226. More particularly, terminals 438 slide along tapered tips 228 untilguide pins 436 are aligned with guide pin mating apertures 226 andinserted therein. As terminals 438 slide along tapered tips 228,cantilever portions 450, 452 bend to accommodate the displacement.

For example, in FIG. 2, guide pin mating aperture 226 of motherboardterminal 438A is in line, i.e., aligned, with the respective guide pin436. However, an offset 232 exists between guide pin mating aperture 226of daughter card terminal 438B and the respective guide pin 436.Cantilever portions 450, 452 bend, sometimes called deflect, toaccommodate offset 232 and allow easy coupling of terminals 438 torespective connectors 430.

FIG. 3 is a cross-sectional view of a blade 118B and bulkhead assembly116A in accordance with another embodiment. Blade 118B is similar toblade 118A of FIG. 2 and only the significant differences between blades118A and 118B are discussed below.

In accordance with the embodiment as illustrated in FIG. 3, springs 560,e.g., helical springs, spring washers, or other elastic members, areplaced between standoffs 448 and daughter card 442. More particularly,springs 560 are placed between daughter card shoulders 218 of standoffs448 and daughter card 442 and around threaded screws 220. Standoffs 448are mounted to motherboard 440. Springs 560 are resilient members thusallowing daughter card 442 to move relative to standoffs 448 and thusrelative to motherboard 440.

Further, springs 562, e.g., similar to springs 560 including helicalsprings, spring washers, or other elastic members, are placed betweenscrew heads 224 of threaded screws 220 and daughter card 442 and aroundthreaded screws 220.

In one embodiment, threaded screws 220 included partially threaded screwportions 564. Partially threaded screw portions 564 included threadedportions 566 and solid portions 568. Threaded portions 566 have threads.In contrast, solid portions 568 having a solid outer surface, e.g., acylindrical surface having an absence of threads.

Threaded portions 566 are threaded into threaded apertures 216 ofstandoffs 448 until solid portions 568 reach threaded apertures 216 anddaughter card shoulders 218. As solid portions 568 lack mating threadsof threaded apertures 216, solid portions 568 prevent further threadingof threaded screws 220 into threaded apertures 216. Accordingly, solidportions 568 precisely set the height of screw heads 224 above daughtercards shoulders 218 of standoffs 448 to give a precise amount of floatfor daughter card 442. Further, solid portions 568 prevent threadedscrews 220 from being over tightened and inhibiting float of daughtercard 442.

Springs 560, 562 allow daughter card 442 and/or motherboard 440 to moveto match any offset between terminals 438A, 438B and connectors 430 ofbulkhead assembly 116A without damage to blade 118B. More particularly,springs 560, 562 allow daughter card 442 and/or motherboard 440 to floatboth up and down, i.e., vertically, from a nominal position.

Stated another way, floating daughter card 442 eliminates the bindingcondition by allowing the entire daughter card 442 and/or motherboard440 to float. Springs 560, 562 and standoffs 448 effectively provide acompliant standoff between daughter card 442 and motherboard 440allowing daughter card 442 and/or motherboard 440 the freedom to float.

Although both springs 560, 562 are illustrated and discussed above, inanother embodiment, only springs 560 or springs 562 are used. Forexample, only springs 560 are used such that screw heads 224 directlycontact daughter card 442 allowing daughter card 442 the freedom to movecloser to motherboard 440 only. As another example, only springs 562 areused such that daughter card shoulders 218 directly contact daughtercard 442 allowing daughter card 442 the freedom to move away frommotherboard 440 only.

Further, cable interface 444, sometimes called a cable connectionbetween daughter card 442 and motherboard 440, further allows daughtercard 442 and/or motherboard 440 the freedom to float. However, in otherembodiments, cable interface 444 is not provided, e.g., there are nodirect connections or no connections at all between daughter card 442and motherboard 440. In another embodiment, the electrical elements canbe on one or both sides of the standoffs. In yet another embodiment, theelectrical elements can be adjacent either daughter card 442 and/ormotherboard 440.

In another embodiment, a blade includes different types of standoffconnections between daughter card 442 and motherboard 440. For example,a blade includes one or more wiring end standoffs 448B at wiring end 122as illustrated in FIG. 2. Wiring end standoffs 448B hold daughter card442 and motherboard 440 fixed and parallel to each other at wiring end122 with no float. As the position of daughter card 442 and motherboard440 is fixed at wiring end 122, a fixed connector between daughter card442 and motherboard 440 can be used in contrast to a compliant connectorthat accommodates tolerance in the positions. However, in oneembodiment, a compliant connector is used to interconnect daughter card442 to motherboard 440.

Further, the blade includes one or more standoffs 448 including springs560 and/or springs 562 at bulkhead assembly connector ends 120 asillustrated in FIG. 3. Springs 560, 562 allow daughter card 442 to floatrelative to motherboard 440 at bulkhead assembly connector end 120 asdiscussed above.

FIG. 4 is a cross-sectional view of a blade 118C, e.g., a line card, anda bulkhead assembly 116C in accordance with yet another embodiment.Blade 118C of FIG. 4 is similar to blade 118A of FIG. 2 except thatdaughter card 442 is fixed in position to motherboard 440 such thatterminals 438A, 438B are fixed in position relative to one another. Asthe position of daughter card 442 and motherboard 440 is fixed, a fixedconnector between daughter card 442 and motherboard 440 can be used incontrast to a compliant connector that accommodates tolerance in thepositions. However, in one embodiment, a compliant connector is used tointerconnect daughter card 442 to motherboard 440.

In accordance with this embodiment, connectors 430 include a fixedconnector 430A and a floating connector 430B. Fixed connector 430A isfixed in position, e.g., with a screw 770, to a bulkhead 112C. Incontrast, floating connector 430B floats, i.e., moves within a definedrange, relative to bulkhead 112C. For example, floating connector 430Bis connected to bulkhead 112C by a shouldered screw 772.

More particularly, floating connector 430B has an opening 234 with adiameter D1 larger than a diameter D2 of a shaft 236 of shouldered screw772. Shaft 236 of shouldered screw 772 is located within opening 234 offloating connector 430B. As opening 234 has a larger diameter D1 thandiameter D2 of shaft 236, floating connector 430B can move relative toshouldered screw 772 and bulkhead 112C.

Accordingly, floating connector 430B can float to accommodate anytolerance in the position of terminals 438 of daughter card 442 and/ormotherboard 440. Floating connector 430B can float up and down, i.e.,vertically, and/or left and right, i.e., horizontally. The amount offloat is defined by the dimensions of shaft 236 and opening 234. In oneembodiment, the float is asymmetric, e.g., in one direction. Further,cables 432 connected to floating connector 430B are flexible thusallowing floating connector 430B to move.

Further, in the embodiment shown, guidepins 436 include a fixedconnector guidepin 436A of fixed connector 430A and a floating connectorguidepin 436B of floating connector 430B. Fixed connector guidepin 436Ais longer than floating connector guidepin 436B.

Thus, during coupling of blade 118C to bulkhead assembly 116C, fixedconnector guidepin 436A engages motherboard 440 before floatingconnector guidepin 436B engages daughter card 442. Thus motherboard 440and daughter card 442 are fixed in position relative to fixed connector430A first. Then floating connector 430B floats to accommodate theposition of daughter card 442, e.g., in the vertical and/or horizontaldirections.

FIG. 5 is a top plan view of a blade 118D and a bulkhead assembly 116Din accordance with another embodiment. FIG. 6 is a cross-sectional viewof blade 118D and bulkhead assembly 116D along the line VI-VI of FIG. 5in accordance with one embodiment.

Referring now to FIGS. 5 and 6 together, blade 118D includes at leastone board 240. For example, board 240 includes a printed circuit boardand various electrical components coupled thereto (not shown). Board 240is any type of board, e.g., is similar to motherboard 440 or daughtercard 442 as discussed above, or other boards depending upon theparticular application.

However, in accordance with this embodiment, board 240 includes aplurality of terminals 438 substantially within a plane of board 240.Further, bulkhead assembly 116D includes a plurality of respectiveconnectors 430 for mating with terminals 438 of board 240. Connectors430 are fixed in position on a bulkhead 112D.

To accommodate tolerance, sometimes called offset, between terminals 438and connectors 430, board 240 is formed with a plurality of flexiblefingers 242. Terminals 438 are coupled to fingers 242.

In accordance with this embodiment, a slot 244 is formed betweenrespective fingers 242. Fingers 242 protrude from a main board portion246 of board 240. In one embodiment, the printed circuit board of board240 is cut between terminals 438 to form slots 244 and define fingers242.

Fingers 242 are flexible and can bend from main body portion 246 toaccommodate offset between terminals 438 and respective connectors 430as indicated by the arrows 248 in FIG. 6.

Although blade 118D is illustrated as only including a single board 240,in other embodiments, blade 118D includes a plurality of boards, e.g.,includes a motherboard 440 coupled to a daughter card 442 as discussedin any of the embodiments above. One, some, or all of the boards caninclude a plurality of terminals 438 including respective flexiblefingers 242 as described above in regards to board 240.

The drawings and the forgoing description gave examples of embodiments.The scope of the embodiments, however, is by no means limited by thesespecific examples. Numerous variations, whether explicitly given in thespecification or not, such as differences in structure, dimension, anduse of material, are possible.

What is claimed is:
 1. An electronic device comprising: a first board; a second board; standoffs coupling the first board to the second board, wherein cantilever portions of the first board and the second board exist between the standoffs and terminals of the first board and the second board.
 2. The electronic device of claim 1 wherein the cantilever portions are configured to accommodate tolerance in the positioning of the terminals of the first board and the second board.
 3. The electronic device of claim 1 further comprising a bulkhead assembly comprising connectors, the cantilever portions bending to accommodate misalignment between the terminals of the first board and the second board and the connectors.
 4. The electronic device of claim 1 further comprising connectors configured to mate with the terminals, the cantilever portions bending to accommodate any misalignment between the terminals of the first board and the second board and the connectors.
 5. The electronic device of claim 4 wherein a distance exists between the standoffs and the terminals of the first board and the second board, the distance being sufficiently great so that the first board and the second board can bend to accommodate the misalignment without damage to the first board and the second board.
 6. The electronic device of claim 5 wherein the allowable amount of bending is 0.010 inches deflection per 1.00 inch of coplanar distance of the first board and the second board.
 7. The electronic device of claim 1 wherein the first board comprises: a plurality of flexible fingers; and a plurality of the terminals within a plane of the first board and coupled to the fingers.
 8. An electronic device comprising: a bulkhead; a fixed connector coupled to the bulkhead; and a floating connector coupled to the bulkhead, wherein the fixed connector is fixed in position relative to the bulkhead and the floating connector is moveable relative to the bulkhead.
 9. The electronic device of claim 8 further comprising: a fixed connector guidepin coupled to the fixed connector; and a floating connector guidepin coupled to the floating connector, wherein the fixed connector guidepin is longer than the floating connector guidepin.
 10. The electronic device of claim 8 further comprising: a fixed screw mounting the fixed connector to the bulkhead; and a shouldered screw mounting the floating connector to the bulkhead, wherein the floating connector has an opening, the shouldered screw having a shaft within the opening, the opening having a first diameter larger than a second diameter of the shaft.
 11. The electronic device of claim 10 wherein the floating connector is moveable asymmetrically.
 12. The electronic device of claim 8 further comprising: a first board comprising a first terminal configured to mate with the fixed connector; and a second board comprising a second terminal configured to mate with the floating connector, wherein the floating connector is configured to accommodate tolerance in the positioning of the first and second terminals with respect to the fixed connector and the floating connector.
 13. The electronic device of claim 12 wherein the first board comprises: a plurality of flexible fingers; and a plurality of the terminals within a plane of the first board and coupled to the fingers.
 14. An electronic device comprising: a first board; a second board; a standoff coupling the first board to the second board, wherein the first board comprises a bendable cantilever portion between the standoff and a terminal of the first board.
 15. The electronic device of claim 14 wherein the second board comprises a bendable cantilever portion between the standoff and a terminal of the second board.
 16. The electronic device of claim 14 wherein a distance exists between the standoff and the terminal of the first board, the distance being sufficiently great so that the first board can bend to accommodate misalignment without damage to the first board, wherein the allowable amount of bending is 0.010 inches deflection per 1.00 inch of coplanar distance of the first board.
 17. The electronic device of claim 14 wherein the first board further comprises: a plurality of flexible fingers; and a plurality of the terminals within a plane of the first board and coupled to the fingers.
 18. The electronic device of claim 17 wherein the first board further comprises a main board portion, the flexible fingers protruding from the main board portion.
 19. The electronic device of claim 17 further comprising slots between the flexible fingers.
 20. The electronic device of claim 17 wherein the second board further comprises: a plurality of flexible fingers; and a plurality of terminals within a plane of the second board and coupled to the fingers of the second board. 